This invention is an improvement in known methods of setting, or resetting poles in the ground, ground line protection of poles or encapsulation of pole treatment chemicals and enhancement of the strength to density ratio, of rigid foam polyurethane resins formed in-situ from polyisocyanate and resin reactive therein. Ground water and detrimental natural soil chemicals are often encountered in pole setting and these affect polyurethane foam formation by undesirably reacting with the polyisocyanate to give a foam of insufficient density and strength.
The present invention is an improvement in the invention disclosed in U.S. Pat. Nos. 3,968,657 to Hannay, 3,564,859 to Goodman, 3,403,520 to Goodman, and 4,966,497 to Kirby which describe related methods for resetting poles with foam plastic. The entire disclosures of U.S. Pat. Nos. 3,968,657, 3,564,859, 3,403,520, and 4,966,497 are incorporated herein by reference.
In brief, U.S. Pat. No. 3,403,520 describes a method of setting pole forms in the ground by making a hole which is only slightly larger than the butt of the pole to be placed in the hole, placing the pole in the hole in the desired position, partially filling the hole with a reactive component mixture with a synthetic resin and a blowing agent and permitting the reaction to complete so as to expand the resinous foam into all the space between the pole and the sides of the hole. The expanded resinous foam adheres to and seals to the lower end of the pole protecting it from moisture, chemicals and rodents and sets the pole in the hole. The expanding resinous foam fills all the voids, surfaces, crevices and notches in the sides and bottom of the hole.
U.S. Pat. No. 3,564,859 describes a procedure for straightening and refilling the hole. It utilizes the same method as U.S. Pat. No. 3,403,520 for producing foam and for filling voids resulting when an existing installed pole has been realigned after it has been canted or tilted.
U.S. Pat. No. 3,968,657 was an improvement upon these methods using the addition of a non-volatile water-immiscible material to the mixture so that properties of the resultant product are not affected excessively in the presence of groundwater.
U.S. Pat. No. 4,966,497 describes a procedure that is an improvement on the above methods because halogenated hydrocarbon blowing agents, more particularly chlorofluorocarbons, are not required. Further, the composition decreased the cost per unit of the polyurethane foam.
The present invention decreases the cost per unit of foam pole installation, and improves its storage stability and reaction reliability, yet maintains the advantageous physical characteristics of previous methods.